The number of persons who were marginally attached to the labor force totaled 1.6 million in March, about the same as a year earlier. (Data are not seasonally adjusted.) These individuals wanted and were available to work and had looked for a job sometime in the prior 12 months. They were not counted as unemployed, however, because they did not actively search for work in the 4 weeks preceding the survey.
Add those 1.6 to the basic 8.4 million and you get 10 million. But wait, there is more.
In March, the number of persons who worked part time for economic reasons increased to 4.7 million, about the same level as in January. These individuals indicated that they would like to work full time but were working part time because their hours had been cut back or because they were unable to find full-time jobs.
It doesn't say how many, but there are probably another 2 to 3 million jobs that would be needed to satify these people.
On top of that is an uncertain number of the newly "self employed consultants" who are not listed as unemployed despite having no work. And an unknown number of people who are not listed as part of the work force but would take jobs if they could find a decent one, such as people who took an early retirement because they couldn't find work.
All things considered, I wouldn't be surprised if you could add some 15 million jobs before you began to squeeze the job market.
Jay